CODEWITHSUNDEEP
c#stringmethods
sabhrish balasubramanian
sabhrish balasubramanian

Reputation: 19

C# - Convert a string (which contains method or function) to an actual function or method in C#

I have a string. For example

 string str="if(a>b) {return a;} else {return b;}"

I want to evaluate or make function, say func(int a, int b) which will have the code of 'str'.

Upvotes: 0

Views: 109

Answers (2)

syazdani
syazdani

Reputation: 4868

In general, this is not an easy thing to do, but the System.CodeDom namespace is where your journey will start.

Look at the following CodeProject article on the matter as a start: http://www.codeproject.com/Articles/26312/Dynamic-Code-Integration-with-CodeDom

The basics of it is as follows (as taken from the codeproject article):

private static Assembly CompileSource( string sourceCode )
{
   CodeDomProvider cpd = new CSharpCodeProvider();
   CompilerParameters cp = new CompilerParameters();
   cp.ReferencedAssemblies.Add("System.dll");
   //cp.ReferencedAssemblies.Add("ClassLibrary1.dll");
   cp.GenerateExecutable = false;
   // Invoke compilation.
   CompilerResults cr = cpd.CompileAssemblyFromSource(cp, sourceCode);

   return cr.CompiledAssembly;
}

The resultant assembly will have the class/method/code you are interested in, and then you can use reflection to call your method. Since your example just uses a code fragment, you will probably have to wrap it in a class/method before passing it to this method.

I hope that helps, but dynamic code generation in C# is not easy and this is just a start.

Upvotes: 1

farid bekran
farid bekran

Reputation: 2754

you may need to use CSharpCodeProvider as in this answer

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.CSharp;
using System.CodeDom.Compiler;

class Program
{
    static void Main(string[] args)
    {
        var csc = new CSharpCodeProvider(new Dictionary<string, string>() { { "CompilerVersion", "v3.5" } });
        var parameters = new CompilerParameters(new[] { "mscorlib.dll", "System.Core.dll" }, "foo.exe", true);
        parameters.GenerateExecutable = true;
        CompilerResults results = csc.CompileAssemblyFromSource(parameters,
        @"using System.Linq;
            class Program {
              public static void Main(string[] args) {
                var q = from i in Enumerable.Range(1,100)
                          where i % 2 == 0
                          select i;
              }
            }");
        results.Errors.Cast<CompilerError>().ToList().ForEach(error => Console.WriteLine(error.ErrorText));
    }
}

Upvotes: 1

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